Editor's note: In the last of this three-part series on hiring skilled employees, Hill deals with the skills test.

Hiring people with the knowledge and skills you require is not an easy or predictable task. Later you often find they don't quite have the skill set you needed or their knowledge has little depth to it. The only way to determine if potential employees have what you need is to test them.

The tests can be simple replicas of the type of measurements or calibration situations they will face. If they maintain they've "been there and done that" in previous jobs, they won't be intimidated by testing.

If the applicant claims to know how to use an outside micrometer, have one available along with some calibrated plain plug gage members that can be measured. Provide a form or sheet of paper for the applicant to write down the sizes. It may prove informative to have some of your staff do the same thing so you have a working benchmark. You may discover that some of your existing people need shaping up. Do a similar test with calipers but add some plain ring gages to see how skilled they are using them for internal measurements. You can do all sorts testing using components made at your plant as test pieces.

When gage blocks are required for your work, you want to ensure the applicant knows how to select the correct sizes for a build-up and whether he does so in an organized way, including corrections for variations shown on their calibration report. Have a set there with a piece of paper to list the blocks he would use to produce the sizes you have listed. Then pick one size and ask what blocks he would select if all of his first choices were in use by someone else.

Assuming the applicant has not collapsed in a quivering heap at this point, the next step is to determine how well he or she can wring gage blocks together. Have three or four blocks that, when wrung together, provide a buildup of 1 inch or 25 millimeters in length. Compare the buildup to a 1-inch or 25-millimeter block using a high-resolution comparator. Make allowances for the calibrated values of all the blocks involved. A gage block deburring stone should be available in the event it is needed.

In between the hands-on tests, you could have a list of questions to help you assess the depth of knowledge an applicant possesses. Having sample parts on hand is helpful and all you need do is ask questions such as: How would you measure the overall length of this feature or this diameter?

If the applicant never asks what the tolerances are on the features you're discussing, it would indicate his knowledge has little depth. You may be interviewing an instrument reader who believes every number the equipment produces. And speaking of numbers, if you have a lot of nondigital instruments, set up potential employees with readings and make sure he can read them.

The applicant who indicates that a coordinate measuring machine is the answer for every application you discuss may know little or nothing about dimensional metrology. This may not be a problem if you have lots of idle measuring machines and the applicant actually knows how to use one.

It's important to put applicants at ease during the interview and tests by indicating that you understand that they may be a bit nervous. Tell them to take their time. Give them an office or quiet area of the inspection department to work in.

You may consider having a couple of your regular employees show them the work area. Your employees will soon tell you if they think you're courting a future problem. And quite often the applicant will reveal more to them than to you. If employees feel all warm and fuzzy about an applicant, that can be a sign that the person would be a good fit for your company.

Consider hiring applicants on a three-month, no-fault trial basis. At the end of the period if they're exactly what you want, they go on staff, if not, they're gone, and you start over. They, of course, have the option to leave, no questions asked.

Because common sense is not so common any more, it's always wise to let new hires know that you expect them to be at work on time every day.